After many requests we have created a compact, special balun for single band loop (Sky loop or Delta loop) antennas with specific dimension that present a feedpoint of 70-75 ohms. The CB-1.5-1-1500/5000 is a CUBE(TM) enclosure containing a multi-core, broadband 1.5:1 impedance transformer (50 ohm coax input to 75 ohm balanced output) in series with a 1:1 current balun for extra common mode current choking to keep RF current off the outside of the coax braid and on the antenna where it belongs. The extra choking action also means that the coax feed line will not act as a radiator causing unnecessary RF interference (RFI). Rated for full 1500 watts PEP and 1500 watts CW (ICAS), 1KW Digital. 1.8Mhz – 61 MHz.
CB-1.5-1-1500EB is housed in a 4” x 4” x 2” waterproof housing with SO-239 input and stainless steel eye bolts on the side for ease of connection to your wire antenna (or top studs as desired). Top eye bolt acts as an antenna hoist. Also available with top studs for post or wall mounting (Model # CB-1.5-1-1500/5000TS). 5KW models are in a 4 " x 4" x 4" housing.
Loop antennas should be cut for 1005/F(MHz) in total length, where F (MHz) is the lowest frequency to be used. For 3.5MHz this equates to 288 foot perimeter (square, delta, multi-side ok). Vertical loops with pointy side up and longer bases and fed 1/4 wavelength down one side have a feed point impedance near 75 ohms for which this balun is well suited. A very good DX antenna!
For unbalanced 50 ohm input to unbalanced 75 ohm output use the CU-1.5-1500 or CU-1.5-5000.
We specify impedance ratios as an output to input ratio where the output (or load) is given first and the input is given second (e.g. 100:50 (2:1) would mean a 100 ohm output and a 50 ohm input; a 25:50 (1:2) would mean a 25 ohm load and a 50 ohm input). Most all products use a 50 ohm input unless otherwise specified.
We have products that are available as kits for the do-it-yourself (DIY) person or fully assembled and tested units for the “Plug & Play” crowd.
Our impedance transformers are available using two different topologies: Binocular cores or toroid cores with multiple turns for increased effectiveness and wide band frequency transformations. We utilize single and multiple core transformers using high order windings when needed to extend product performance.
We rate the power ratings as watts PEP (Peak Envelop Power) with standard duty cycles for various modes. To determine the PEP rating required for your needs, see: Choke & Transformer Power Ratings
This website page serves as a link page to the frequency ranges of our impedance transformers configured as either baluns or ununs. You can click on a picture to go to the specific page about the products described in the picture.